There are many different dispensers which are utilised to dispense a metered dose of a product such that the dose can be self-administered, by the patient, under the direction of a physician, such dispensers including primarily aerosol dispensers relying upon a pressurised dispensing container having a metering valve and pump dispensers having a pump chamber arranged to dispense a metered dose. It is important to regulate use of the dispenser, to avoid overdosing where the product is a potentially dangerous or expensive drug.
Lock-out mechanisms have been disclosed, for example in U.S. Pat. No. 4,934,358, for preventing actuation of an inhalation dispenser other than in accordance with a predetermined dosing schedule. Similarly, GB2368061A discloses a locking mechanism to prevent further dispensing until electronically released in accordance with a desired dispensing program.
It is also known from WO03/097141, for a dispensing system to be provided with a control circuit which can be programmed to provide a dosing regime in accordance with the requirements of a physician.